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| /** |
| * \addtogroup uip |
| * @{ |
| */ |
| |
| /** |
| * \defgroup slip Serial Line IP (SLIP) protocol |
| * @{ |
| * |
| * The SLIP protocol is a very simple way to transmit IP packets over |
| * a serial line. It does not provide any framing or error control, |
| * and is therefore not very widely used today. |
| * |
| * This SLIP implementation requires two functions for accessing the |
| * serial device: slipdev_char_poll() and slipdev_char_put(). These |
| * must be implemented specifically for the system on which the SLIP |
| * protocol is to be run. |
| */ |
| |
| /** |
| * \file |
| * SLIP protocol implementation |
| * \author Adam Dunkels <adam@dunkels.com> |
| */ |
| |
| /* |
| * Copyright (c) 2001, Adam Dunkels. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. The name of the author may not be used to endorse or promote |
| * products derived from this software without specific prior |
| * written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS |
| * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
| * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE |
| * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| * This file is part of the uIP TCP/IP stack. |
| * |
| * $Id: slipdev.c,v 1.1.2.3 2003/10/07 13:23:01 adam Exp $ |
| * |
| */ |
| |
| /* |
| * This is a generic implementation of the SLIP protocol over an RS232 |
| * (serial) device. |
| * |
| * Huge thanks to Ullrich von Bassewitz <uz@cc65.org> of cc65 fame for |
| * and endless supply of bugfixes, insightsful comments and |
| * suggestions, and improvements to this code! |
| */ |
| |
| #include "uip.h" |
| |
| #define SLIP_END 0300 |
| #define SLIP_ESC 0333 |
| #define SLIP_ESC_END 0334 |
| #define SLIP_ESC_ESC 0335 |
| |
| static u8_t slip_buf[UIP_BUFSIZE]; |
| |
| static u16_t len, tmplen; |
| static u8_t lastc; |
| |
| /*-----------------------------------------------------------------------------------*/ |
| /** |
| * Send the packet in the uip_buf and uip_appdata buffers using the |
| * SLIP protocol. |
| * |
| * The first 40 bytes of the packet (the IP and TCP headers) are read |
| * from the uip_buf buffer, and the following bytes (the application |
| * data) are read from the uip_appdata buffer. |
| * |
| */ |
| /*-----------------------------------------------------------------------------------*/ |
| void |
| slipdev_send(void) |
| { |
| u16_t i; |
| u8_t *ptr; |
| u8_t c; |
| |
| slipdev_char_put(SLIP_END); |
| |
| ptr = uip_buf; |
| for(i = 0; i < uip_len; ++i) { |
| if(i == 40) { |
| ptr = (u8_t *)uip_appdata; |
| } |
| c = *ptr++; |
| switch(c) { |
| case SLIP_END: |
| slipdev_char_put(SLIP_ESC); |
| slipdev_char_put(SLIP_ESC_END); |
| break; |
| case SLIP_ESC: |
| slipdev_char_put(SLIP_ESC); |
| slipdev_char_put(SLIP_ESC_ESC); |
| break; |
| default: |
| slipdev_char_put(c); |
| break; |
| } |
| } |
| slipdev_char_put(SLIP_END); |
| } |
| /*-----------------------------------------------------------------------------------*/ |
| /** |
| * Poll the SLIP device for an available packet. |
| * |
| * This function will poll the SLIP device to see if a packet is |
| * available. It uses a buffer in which all avaliable bytes from the |
| * RS232 interface are read into. When a full packet has been read |
| * into the buffer, the packet is copied into the uip_buf buffer and |
| * the length of the packet is returned. |
| * |
| * \return The length of the packet placed in the uip_buf buffer, or |
| * zero if no packet is available. |
| */ |
| /*-----------------------------------------------------------------------------------*/ |
| u16_t |
| slipdev_poll(void) |
| { |
| u8_t c; |
| |
| while(slipdev_char_poll(c)) { |
| switch(c) { |
| case SLIP_ESC: |
| lastc = c; |
| break; |
| |
| case SLIP_END: |
| lastc = c; |
| /* End marker found, we copy our input buffer to the uip_buf |
| buffer and return the size of the packet we copied. */ |
| memcpy(uip_buf, slip_buf, len); |
| tmplen = len; |
| len = 0; |
| return tmplen; |
| |
| default: |
| if(lastc == SLIP_ESC) { |
| lastc = c; |
| /* Previous read byte was an escape byte, so this byte will be |
| interpreted differently from others. */ |
| switch(c) { |
| case SLIP_ESC_END: |
| c = SLIP_END; |
| break; |
| case SLIP_ESC_ESC: |
| c = SLIP_ESC; |
| break; |
| } |
| } else { |
| lastc = c; |
| } |
| |
| slip_buf[len] = c; |
| ++len; |
| |
| if(len > UIP_BUFSIZE) { |
| len = 0; |
| } |
| |
| break; |
| } |
| } |
| return 0; |
| } |
| /*-----------------------------------------------------------------------------------*/ |
| /** |
| * Initialize the SLIP module. |
| * |
| * This function does not initialize the underlying RS232 device, but |
| * only the SLIP part. |
| */ |
| /*-----------------------------------------------------------------------------------*/ |
| void |
| slipdev_init(void) |
| { |
| lastc = len = 0; |
| } |
| /*-----------------------------------------------------------------------------------*/ |
| |
| /** @} */ |
| /** @} */ |